Power transmission

ABSTRACT

A rotary sliding vane pump or motor has pressure loaded cheek plates on each side of the revolving rotor and vanes. The cam ring has alternate major and minor diameter circular arcs connected by rising and falling ramps along which fluid displacement occurs. End covers and cheek plates of similar configuration enclose the end faces of the cam ring, rotor and vanes. The cheek plates have pressure loading cavities of circular form opposite each ramp. All of the cavities on each end are connected with a terminal in the adjacent end cover and alternate cavities are perforated to provide fluid passages into the working chambers of the device. The intermediate cavities on each cheek plate are blind. The cheek plates are so located that a perforated cavity on one end lies opposite a blind cavity on the other end of the device and the areas of the cavities are chosen to slightly overbalance the pressure forces existing at the interface between the rotor and cheek plates.

United States Patent 91 Pettibone et al.

[ POWER TRANSMISSION [75] Inventors: Raymond B. Pettibone, Troy; Albin J. Niemiec, Sterling Heights, both of Mich.

[73] Assignee: Sperry Rand Corporation, Troy,

Mich.

[22] Filed: Dec. 21, 1972 [21] Appl. No.: 317,437

Primary Examiner--C. .J. Husar Assistant ExaminerLeonard Smith Attorney, Agent, or Firm-Theodore Van Meter [451 Feb. 19,1974

[57] ABSTRACT A rotary sliding vane pump or motor has pressure loaded cheek plates on each side of the revolving rotor and vanes. The cam ring has alternate major and minor diameter circular arcs connected by rising and falling ramps along which fluid displacement occurs. End covers and cheek plates of similar configuration enclose the end faces of the cam ring, rotor and vanes. The cheek plates have pressure loading cavities of circular form opposite each ramp. All of the cavities on each end are connected with a terminal in the adjacent end cover and alternate cavities are perforated to provide fluid passages into the working chambers of the device. The intermediate cavities on each cheek plate are blind. The cheek plates are so located that a perforated cavity on one end lies opposite a blind cavity on the other end of the device and the areas of the cavities are chosen to slightly overbalance the pressure forces existing at the interface between the rotor and cheek plates.

5 Claims, 3 Drawing Figures POWER TRANSMISSION Rotary sliding vane pumps and motors present serious sealing problems along the end faces of the rotary parts and these problems increase in difficulty as the operating pressures are increased. It has long been a practice to provide pressure loaded cheek plates on one or both ends of the revolving group to counteract the tendency of the high pressure fluid to separate the stationary from the rotating parts at this interface. In applications where the high pressure side is always at one terminal of the unit, a rather simple design of pressure loaded cheek plate will suffice. But, where the application requires operation with high pressure at either terminal, satisfactory pressure loading of the cheek plates is difficult to achieve without rather complex circuitry involving check valves and a multiplicity ofinternal passages.

It is an object of the present invention to provide an improved design of rotary sliding vane pump or motor in which either terminal may be the high pressure terminal at a given time and in which simple pressure loaded cheek plates provide the proper take-up of the end clearance between the rotary and stationary parts.

This is accomplished by the provision ofa rotary sliding vane pump or motor having a body comprising a central cam ring having circular arcs of major and minor diameters alternately spaced around its inner cam surface and connected by ramps along which fluid displacement can occur, the body further comprising end covers containing fluid terminals and passages connecting the terminal of one cover with. alternately spaced ramps of the cam ring and connecting the terminalof the other cover with the intermediate spaced ramps of the cam ring, a slotted rotor within the cam ring and carrying radially slidable vanes to traverse the cam ring inner surface, cheek plates interposed between each end cover and the rotor and vanes, and means for pressure loading the cheek plates comprising a series of cavities at the interfaces of the cheek plate and end covers, each cavity being peripherally sealed from adjacent cavities, there being one cavity for each ramp with alternate cavities being perforated to carry fluid through the cheek plate and the other cavities being imperforate, the cheek plates being positioned with their perforate cavities lying opposite the imperforate cavities of the other cheek plate, and passages connecting the imperforate cavities of each cheek plate with its adjacent end cover terminal.

IN THE DRAWINGS FIG. 1 is a dihedral cross section on line l-I of FIG. 2 through a vane pump or motor incorporating a preferred form of the present invention.

FIG. 2 is a perspective view of the cam ring, rotor and vanes forming part of the device of FIG. 1.

FIG. 3 is a perspective view of a cheek plate forming part of the device of FIG. 1.

Referring to FIG. 1, the device there illustrated may typically be used as a reversible fluid motor having terminals and 12 which, when fluid under pressure is delivered to one or the other, the motor will be driven in one or the other direction. The body of the unit comprises a central cam ring 14, a pair of similar cheek plates 16 and 18, and a pair of similar end covers 20 and 22. These parts are all clamped together by bolts 24 at suitably placed points around the periphery of the end covers. The revolving group of the unit comprises a slotted rotor 26 having an internal spline 28 for the reception of a driven shaft, not shown, and a series of radially slidable vanes 30 which are spring pressed outwardly against the internal cam surface of the cam ring I4. This surface, as illustrated in FIG. 2, is made up of a plurality of alternately spaced circular arcs, those of major diameter being designated 32 and those of minor diameter being designated 34. These arcs are connected by rising ramps 36 and falling ramps 38. It is as the vanes pass along these ramps that the fluid displacing action of the device occurs, with fluid being taken in along the rising ramps and being exhausted along the falling ramps. The terms rising and falling refer, of corse, to the action when the rotor is revolving clockwise in FIG. 2 and their designation would be reversed upon reversal of rotor rotation.

Referring again to FIG. I, the end coves 20 and 22 are similarly constructed and are provided with cored passages 40 and 42 which connect with the terminals 10 and I2 respectively and open radially inwardly to bores 44 and 46 in the end covers. These bores are closed by sleeves 48 which are sealed to the bore 46 on either side of the cores 40 and 42. Intercepting the cores 40 and 42 are a series of eight machined passages 50 and 52 in each end cover. These passages lie opposite the ramps 36 and 38 and extend inwardly to the inner face of each end cover.

Referring to FIG. 3, the configuration of cheek plate 16 is there illustrated, and is also representative of the other cheek plate I8, the two being identical. The inner face of the plate I6 is flat except for an O-ring sealing groove 54. The back face is provided with a series of eight circular cavities 56 and 58. The cavities 56 are blind; that is, their bottoms are imperforate, while the cavities 58 have through passages 60 and 62 which form fluid passageways through which fluid passes to and from the working chambers formed by the rotor, the vanes and the cam ring. O-ring seals such as 65 are provided at the periphery of each cavity 56 and 58. The cheek plates I6 and 18 are so positioned when the device is assembled that each imperforate cavity 56 of the cheek plate I6 lies opposite a perforated cavity 58 of the cheek plate 18, as illustrated at the top of FIG. I.

In operation when fluid is admitted under pressure to one of the terminals, for example terminal I0, it will pass through the cored passage 40 and the machined passages 50 into all eight of the cavities 56 and 58 of cheek plate 16. It will then pass through the four perforations 60 to four of the rising ramps 36 and drive the rotor clockwise in FIG. 2. Fluid will be exhausted from the falling ramps 33 through machined passages 52 and cores 42 to the terminal 12. The pressure required to drive the load which isconnected to the splined connection 28 of the rotor will be applied in all of the cavities 56 and 58 of the cheek plate 16. That in the cavities 56 will be applied only on the outer side of the cheek plate, while that in the cavities 58 will be transmitted equally to both the inner and outer faces of the cheek plate 16. Thus, fluid pressure is supplied over the total area of the four cavities 56 in a direction urging the cheek plate I6 more tightly against the revolving group. The cavities 56 and 58 of the opposite cheek plate 18 are at the same time subjected only to pressure at the outlet terminal I2 which is nominally low.

The areas of the cavities 56 and 58 are so chosen that their total force will more than equal the total force of the areas at the interface between cheek plate 16 and the revolving group which are subjected to pressure and thus will tend to close the clearance at that interface as the operating pressure rises. Since the two cheek plates are identical as are the end covers, when rotation of the motor is reversed by the application of pressure fluid to the terminal 12, a similar action will take place, causing the cheek plate 18 to tend to seal the running clearance at the interface with the revolving group and the cheek plate.

We claim:

1. A rotary sliding vane pump or motor having a body comprising a central cam ring having circular arcs of major and minor diameters alternately spaced around its inner cam surface and connected by ramps along which fluid displacement can occur, said body further comprising end covers containing fluid terminals and passages connecting the terminal of one cover with alternately spaced ramps of the cam ring and connecting the terminal of the other cover with the intermediate spaced ramps of the cam ring, a slotted rotor within the cam ring and carrying radially slidable vanes to traverse the cam ring inner surface, cheek plates interposed between each end cover and the rotor and vanes, and

means for pressure loading the cheek plates comprising a series of cavities at the interfaces of the cheek plate and end covers, each being peripherally sealed from adjacent cavities, there being one cavity for each ramp, with alternate cavities being perforated to carry fluid through the cheek plate and the other cavities being imperforate, the cheek plates being positioned with their perforate cavities lying opposite the imperforate cavities of the other cheek plate, and passages connecting the imperforate cavities of each cheek plate with its adjacent cover terminal.

2. A pump or motor as defined in claim 1 wherein the caivities are all of the same area.

3. A pump or motor as defined in claim 1 wherein the imperforate cavities have a total area sufficient to overbalance the summed pressure forces acting to separate the cheek plate from the rotor and vanes.

4. A pump or motor as defined in claim 1 wherein the cheek plates have their outer portions clamped between the end covers and the cam ring.

5. A pump or motor as defined in claim 2 wherein 

1. A rotary sliding vane pump or motor having a body comprising a central cam ring having circular arcs of major and minor diameters alternately spaced around its inner cam surface and connected by ramps along which fluid displacement can occur, said body further comprising end covers containing fluid terminals and passages connecting the terminal of one cover with alternately spaced ramps of the cam ring and connecting the terminal of the other cover with the intermediate spaced ramps of the cam ring, a slotted rotor within the cam ring and carrying radially slidable vanes to traverse the cam ring inner surface, cheek plates interposed between each end cover and the rotor and vanes, and means for pressure loading the cheek plates comprising a series of cavities at the interfaces of the cheek plate and end covers, each being peripherally sealed from adjacent cavities, there being one cavity for each ramp, with alternate cavities being perforated to carry fluid through the cheek plate and the other cavities being imperforate, the cheek plates being positioned with their perforate cavities lying opposite the imperforate cavities of the other cheek plate, and passages connecting the imperforate cavities of each cheek plate with its adjacent cover terminal.
 2. A pump or motor as defined in claim 1 wherein the caivities are all of the same area.
 3. A pump or motor as defined in claim 1 wherein the imperforate cavities have a total area sufficient to over-balance the summed pressure forces acting to separate the cheek plate from the rotor and vanes.
 4. A pump or motor as defined in claim 1 wherein the cheek plates have their outer portions clamped between the end covers and the cam ring.
 5. A pump or motor as defined in claim 2 wherein each cavity is circular in form. 